<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>html_表单</title>
</head>
<body>
<form action="" method="post">
    用户名：<input type="text" name="username" id="">
    年龄：<input type="text" name="age">
    <input type="submit" value="提交">
</form>
</body>
</html>